PhET : Picture 2: How experiment page will look like. Procedure: 1. Check unstretched length box. 2. Pick mass 50 g by selecting arrow key to 50 g. 3. Now you are ready to start your experiment. Hang 50 g mass to the spring and spring will start oscillating. 4. Look at the bottom right to the page and click "slow". Now spring will oscillate slowly. Now click to movable line and fix it to the 2nd end point of the oscillation. 5. Spring will oscillate between Red and Blue line and these are its end points. The distance between these lines is 2A which means twice of amplitude. 6. Now take stopwatch and record time of one oscillation. For 50 g, it will come 0.56 s. 7. Take Yellow ruler from the right side of the page and measure distance between Red and Blue line which is 16 mm for 50 g case. 8. Now calculate spring constant of the spring, k, using equation you learned. 9. T = 2*pivm/k --- (1) ; Use, k = 4*pi~2*m/T^2 --- (2) and find out k = 6.29 N/m. 10.Now change mass to m=100 g and record time period of oscillation Texp, and find out Ith by plugging m and k in equation # 1. Now find percent error between Texp and Tth. 11. Now change mass to 200 g and find out Texp and Tth and percent error between them. %error = (Tth - Texp)*100/Tth 2